Abstract-Hybrid electronic-photonic subwavelength cavities operating at terahertz frequencies

http://prb.aps.org/abstract/PRB/v87/i4/e041408

E. Strupiechonski¹, G. Xu¹, P. Cavalié², N. Isac¹, S. Dhillon², J. Tignon², G. Beaudoin³, I. Sagnes³, A. Degiron^1,*, and R. Colombelli^1,† 
1Institut d’Electronique Fondamentale, Université Paris Sud and CNRS, UMR8622, 91405 Orsay, France
²Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France
³Laboratoire de Photonique et Nanostructures, CNRS UPR20, 91460 Marcoussis, France

We report on the concept and realization of terahertz (THz) metallic/semiconductor cavities characterized by dimensions as small as λ_eff/9 in all directions of space (or λ/30 with the vacuum wavelength). We experimentally prove that the capacitance and inductance of these devices are not interdependent, as in purely photonic cavities, but that they can be adjusted almost independently, as in an electronic circuit. This functionality proves that the dimensions of these hybrid electronic-photonic devices are intrinsically not limited by diffraction as in conventional photonic resonators. Using arguments from transmission line theory, we show that it is necessary to include at least one metallic loop in the cavity design to access this regime and we note, as a corollary, that some recent proposals to miniaturize THz resonators and devices beyond the diffraction limit do not meet this fundamental requirement. Our results shed a light on the ability to describe THz/metallic cavities in terms of circuit elements. Furthermore, upon insertion of electrical contacts, these extremely subwavelength resonators can potentially lead to advances in THz detectors and phased array antennas.

©2013 American Physical Society